Liberty of thinking, and of expressing our thoughts, is always fatal to priestly power, and to those pious frauds on which it is commonly founded.

Avarice, the spur of industry.

If morality had naturally no influence on human passions and actions, it were in vain to take such pains to inculcate it; and nothing would be more fruitless than that multitude of rules and precepts with which all moralists abound.

.. that which renders morality an active principle and constitutes virtue our happiness, and vice our misery: it is probable, I say, that this final sentence depends on some internal sense or feeling, which nature has made universal in the whole species.

It were better, never to look beyond the present material world. By supposing it to contain the principle of its order within itself, we really assert it to be God; and the sooner we arrive at that divinity, the better.

To hate, to love, to think, to feel, to see; all this is nothing but to perceive.

When the coherence of the parts of a stone, or even that composition of parts which renders it extended; when these familiar objects, I say, are so inexplicable, and contain circumstances so repugnant and contradictory; with what assurance can we decide concerning the origin of worlds, or trace their history from eternity to eternity?